Periodontal diseases are the leading cause of tooth loss in adults. Periodontitis is initiated by tooth-associated subgingival biofilms trigger an altered host response leading to soft tissue inflammation and subsequent bone loss. Periodontal infections are implicated in a variety of other diseases (such as cardiovascular disease, stroke and aspiration pneumonia) whereby the microbial biofilm serves as a “slow delivery system” of oral pathogens adhering to teeth leading to a chronic microbial challenge and downstream effects of an altered host response to the patient. Diagnostic methods in clinical practice today lack the ability to both detect the onset of inflammation and to identify those patients susceptible to future disease progression. Oral-fluid-based point-of-care (POC) diagnostics are commonly used for various diagnostic tests in medicine and more recently are being adapted for the determination of oral diseases (Tabak, 2007, Ann N Y Acad Sci 1098: 7-14). Recent clinical applications use new “lab-on-a-chip, LOC” technologies as rapid POC diagnostics of systemic infectious diseases (Chen et al., 2007, Ann N Y Acad Sci 1098: 429-436; Mauk et al., 2007, Ann N Y Acad Sci 1098: 467-475) and periodontal disease (Herr et al., 2007, Proc Natl Acad Sci USA 104: 5268-5273). The human salivary proteome project, supported by the U.S. National Institute of Craniofacial Research (NIDCR), has further generated emphasis on the use of proteomic markers for disease diagnosis (Wong, 2006, J Am Dent Assoc 137: 313-321).
In oral-based diagnostics, the use of oral fluids has successfully demonstrated its ease of use for POC application (Malamud, 2006, J Am Dent Assoc 137: 284-286) for the detection of oral cancer (Li et al., 2004, Clin Cancer Res 10: 8442-8450; Zimmermann et al., 2008, Oral Oncol. 44(5):425-9) or HIV infection (Delaney et al., 2006, Aids 20: 1655-1660). Furthermore, the use of microfluidic devices as examples of LOC technology offers significant potential for rapid saliva diagnosis for widespread public health purposes (Herr et al., 2007, Proc Natl Acad Sci USA 104: 5268-5273; Yager et al., 2006, Nature 442: 412-418). However, for periodontal disease determination, most research to date has focused primarily on gingival crevicular fluid (GCF) biomarkers that provide local disease status, but represent a cumbersome, difficult to utilize approach for clinical application (Taba et al., 2005, Dent Clin North Am 49: 551-571, vi). Easy-to-access saliva contains both locally and systemically-derived mediators of periodontal disease and thus offers significant potential for the assessment of periodontal disease status and risk (Kinney et al., 2007, Ann N Y Acad Sci 1098: 230-251).
Periodontal and peri-implant disease activity presently are diagnosed by clinical parameters such as pocket depth, bleeding on probing, and radiographs. These parameters have limitations in that they lack ability to predict future attachment loss, and provide information only on the existence of past disease activity. The need for diagnostics in clinical dentistry that are predictive markers of active periodontitis is a focus of present research. Periodontal disease is a general term used to describe specific diseases that affect the gingiva, as well as the supporting connective tissues and alveolar bone that anchor the teeth in the jaws. The periodontal diseases are among the most common infectious diseases in humans. In the last fifteen years, with the decline of dental caries in children aged 6-18, and better prevention programs for the general population, periodontal disease leading to tooth loss has assumed even greater importance.
As more teeth are retained due to reduced cavities, more teeth are at risk to be affected by periodontal disease.
The use of clinical parameters for the diagnosis of periodontal disease has numerous limitations. For example, Haffajee and co-workers (“Clinical risk indicators for periodontal attachment loss,” Journal of Clinical Periodontology, 1991; v. 18:117-125) have demonstrated that no clinical parameters have been shown to be predictive for periodontal disease activity. Thus, there have been intensive research efforts to develop diagnostic tests for periodontal disease evaluation. Over 60 different tests for oral fluid components have been studied with no single oral fluid biomarker demonstrating utility as a clinically available diagnostic (reviewed in Taba et al, “Diagnostic biomarkers for oral and periodontal diseases,” Dental Clinics of North America, 2005; v. 49:551-571).
Despite the plethora of such components, there are at present no diagnostic tests available which have been demonstrated to be highly predictive for periodontal disease. As the breakdown of these components is the ultimate concern of the practitioner, their destruction should be evaluated.
Thus, the recognition and diagnosis of periodontal disease has become even more important, and there exists a need in the art for rapid, accurate and sensitive methods for diagnosing and assessing the degree of periodontal diseases.